1. Field of the Invention
The present invention relates a printing system, a printing method and a printer wherein a plurality of types of information different in priority, such as print data, can be processed according to the priority.
2. Description of the Related Art
In a conventional type printing system, a host computer such as a personal computer generates print data and sends the print data to a printer connected via a network or a local area network. The printer executes a predetermined printing process on a recording medium by interpreting the received print data and driving a print engine.
Data other than print data can be also sent from a host computer to a printer. For example, a host computer can request the status of the printer such as the residual quantity of paper and toner of a printer. A host computer can also request that the printer stop printing in an emergency.
As one logical channel is allocated to a physical interface between a host computer and a printer according to the above prior art, only one type of information can be sent at a time. That is, until data transmission is completed while first data is transmitted from a host computer to a printer, subsequent data cannot be transmitted because the logical channel is occupied until the transmission of the first data is completed.
Therefore, even if the cancellation of printing is requested after print data is sent to a printer, a cancel printing command cannot be sent to the printer until the transmission of all of the print data is completed. Therefore, the prior art has a problem in that data having a high priority, a command for an urgent stop and data for interrupt printing cannot be promptly processed. Further, the prior art is inefficient because only one logical channel is provided.